Uncovering the Truth About Camshaft Hardness: Cam Failure Series Part 2
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- čas přidán 25. 03. 2023
- Lots of talk about camshaft failures and harness is the reason why. Is it? Do you know what hardness on a camshaft looks like? Most have never seen what this video shows. We'll uncover the truth about camshaft hardness and just how fragile cast cores really are.
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#camshaft #camfailure #rockwellhardness - Auta a dopravní prostředky
dude you deserve to have way more subscribers. this is killer info no one else has shown
haha thanks man. I gotta pin this comment. 😆😆
@@MuscleCarSolutions i'll second that.
I keep thinking the same thing. Love these videos.
It's sad that flat tappets realistically aren't a viable option anymore, you used to be able to get those dirt cheap summit cam and lifter sets for under $100 and they had a very good reputation and I have personally used several in the past, now these days even the top shelf high dollar stuff doesn't seem to last, the manufacturers really need to step up their game before they cause more and more people to get out of the car hobby.
We covered a very good cost effective solution in the first video. The reality is, the core suppliers in the US have made it very clear that they no longer want to support the demand. They primarily supply the OEs and they all use roller cams. So going back back forth and for a product like flat tappet cams that don’t make them the same amount of money is signaling the decline in that category. There will be more off shore options as those manufacturers decline. But as mentioned in the first video, it’s the lifters that are primarily to blame. It is sad.
Your reply is very understandable. It's a shame for all us Old School guys that were raised on Flat Tappets, but I get it. We either switch over to Roller or we have to go back and work for a living and do our jobs more thoroughly. First we lost our Zinc in the oil. Then we started relaxing and expecting to rely on our Machinist to watch our backs. Then our great machinist's started retiring and the talent started to slide away. We didn't pay attention to much about valve spring pressures because the Machinist always took care of that for us. Now were losing quality of our lifters and cam cores. So now I have to clean out the cob webs and take control of the job or go roller. Think I'll try both.
@@sonnymiller1486 I’ll try the new lifters on something this year I’m guessing. We’ll see what I can squeeze in.
As I see it the Cam/Lifter retailers have an obligation to specify break in and usage instructions if they are going to continue to sell flat tappet cams and lifters. If the Cam core manufactures continue to produce the product, no matter the demand or popularity they too have an obligation to build the item in a way that allows the cam to last. Otherwise both the retailer and the Core manufacture should simply stop production/selling. Consumers cannot be left holding the bag.
Would be really interesting to see an original cam, a couple decades before these cam failures became common...cut open this way. Original cams I've seen "worn" took 30, 40 years and a couple hunded thousand miles to get that way....and they were still running fine.
I have the one that came out of my GMC truck which was the factory original cam. If I get the time I might cut it open. Though I don’t think we’ll see any difference. The cores I don’t believe are the issue. But we’ll explore that on the next video in this series.
In our Metlab, we check micro structers, density, Rockwell hardness, etc etc. At Borg Warner, we make Trans gears, Pto's, clutches, Connecting Rods, etc. Thanks very much for sharing this important info with us. Cheers from Motown.
There are a few different ways to heat treat different metals. All of them are cool!
I left this comment on your first video.
Back in 1977 I was finishing on a engineering degree with GMI (General Motors Institute).
GM got themselves in a pickle over this same issue.
Over at AC Delphi where the cams and lifters were made, they had issues in the heat treat dept.
with fires and oil clean-up.
In a large basket, the cams and lifters came out of the furnace red hot and was lowered in a vat of oil.
This caused oil splattering everywhere. GM was shelling out big bucks for the Equipment cleaners, EPA, and disposal of the oil.
At GM, we had, at that time, Employee Suggestion Program.
I personally knew of the engineer that suggested that GM use water-hard steel instead of oil-hard steel, that it would eliminate EPA, Fires, Smoke, and water hard steel is cheaper than oil hard.
GM paid that employee 20K and used his suggestion.
That ended with GM having one of the largest recalls, at that time (1978 and part of 1979) with the 305, 307, and some of the 350's with this very issue.
Oil-hard steel case hardened to .0035" thousands and water-hard steel case hardened to only .0015".
Not a whole lot of protection.
Most of your cam and lifter manufactures go on the cheap and use water hard-steel giving you a
.0015" case hardened cam and lifter.
GM used a Non-Detergent oil with a GM EOS additive. It has a lot of zinc.
When GM started these engines on the line, they opened them up immediately to 2200 rpm for 20 mins.
Loved the video. Well done.
Brought back a lot of memories too.
I answered your question on the other video….
Another fun fact from GM,
Back around 2010, the EPA demanded the big 3 produce a catalytic converter
that would last 100K. GM said that's impossible!!!!
The EPA asked why?
GM responded saying the additives in the engine oil is what's causing cats to plug up.
That's when oil producers started removing zddp from your oil.
It added an extra layer of protection to the friction parts of the engine.
And to those who say, Well I just use diesel oil. It has zinc.
Sorry to tell you, Not no more.
Use a non-detergent oil with zddp.
Works every time.
Really Doubt GM or any other Domestic auto maker Used Case Hardened Steel FT camshafts and Lifters......Rockwell 55 Hardened cast Iron was used Not Steel....
@tomstrum6259 Your half right.
GM used cast steel then changed to cast iron.
The lifters need to have the same Rockwell hardness as the cam or the lifters will fail and eat the cam even if it was hardened properly. A chain is only as strong as its weakest link. As a production engineer it comes down to the oven time and it seems to me the oven time period may have been reduced to save on cost of power. This goes for cams and lifters. Bearing races, the good ones have a Rockwell of 90-95. But the mass of the races are not as large as a cam. A production oven usually would have a full oven full of product and do them all at once. A one or 2 at a time would be to inefficient. Cutting corners on the heat treating process to save on cost also would result in what you are seeing on your cutouts.
THANK YOU very Much! You explained that pretty well. Got alot of info out of it. Looking forward to the lifter video. Thanks again.
Thanks! I wanted folks to see what actual hardening looks like. It’s very easy to see when a cam is cut apart. A Rockwell test will give a surface number but this will show just how good it was. Very important to help clear up that confusion. Glad you liked the video!
Thanks ,great video. Please keep them coming.
I have one more planned on lifter crown. Not sure when I’ll have that one done but it will be soon.
I come from the knife world and nerding out on the components and methods and processes that go into creating steel and the benefits and draw backs to manufacturing methods and what can and is done to prevent short comings of say a high hardness and edge retention steel to and less edge retentive but tougher or more ductile steel. Cast steel generally is brittle because during the manufacturing process the steel is poured and cools in a way that doesn’t orient the grain structure in a common direction and leaves voids on a microscopic level throughout the cast part. Forging is where that steel is worked and folded and worked while hot to orient the grain structure in a more common direction and to work out voids or break up the large crystalline structures that come with letting the steel cool off and crystallize in a random orientation. Smaller crystals/carbides oriented in a better =less voids and stronger steel with better properties to take abuse. Billet is where the steel is forged and worked or manufacture before it even leaves the factory where it’s made. The reason it’s done like that is because rather than shaping a set amount of metal in the shape of a cam and trying to orient the grain structure throughout the shape of a cam shaft, the billet of steel has already gone through that process of orienting the grain structure and getting rid of those voids and you cut out a cam from a much bigger block of already worked steel. Less internal stress in a billet as your grain size and crystal structure is uniform throughout the entire billet. More uniformity throughout=more uniform properties throughout the materiel=better heat treat, annealing, ductility, and toughness. The steel becomes more compliment to what you’re trying to get it to do. That’s a very very very basic explanation to the best of my knowledge but that’s steel in general for ya
Another informative video , thanks again!!
Thanks man! Appreciate it!
How about matched materials from the cam also used in the lifters and hardened the same.
Great video very informative
Thanks boss!
I think this was a very good attempt to discuss hardness of a cam shaft. There are going to be differences between manufacturers. The same consideration must be used on the surface of the tappet. And, when one takes two hard surfaces and puts stress on each of the surfaces under load, there are going to be those properties that will cause abrasion imparted on each surface.
It is equally important that the hardness is controlled in the laboratory test to use specific sets for the tests to be performed. That is, increasing loads on each component to find the exact deadly parameter.
Heat treatment is an art that contains many variables. Time,temperature, and concentration of metallic concentration of the desired metals, will make or break the alloy used.
Good stuff 2 learn about great info thanks.
Thanks!
Question for Billy, have you ever checked a cam for rotating balance? Years ago on one of my first experiences helping rebuild a 6 cylinder Ford engine the cam was laying on the work bench, it would roll to the same position every time, We put the engine together and all was well. Now years later I'm still curious about this, one video I watched a while back on the Ford Y block said the cam gear was counter weighed to offset the fuel pump eccentric lobe. The 2 cams in my 4 cylinder Chevy Colorado is most likely in static balance as the 4 lobes on the end are 180 degrees apart and the 4 lobes on the inside are 90 degrees offset from there. This should create a dynamic out of balance while rotating. I understand the the lifters/ cam followers are doing a jumping jack routine to only aggravate the situation further. Please excuse all the verbs, and Thanks in advance for any thoughts on this, Fred.
This is an overlooked aspect.
I’m using Lucas break in oil with high zinc some Redline stuff for the cam for my break in and was planning on following the recommended procedures. Any advice or tips? Also I saw Uncle Tony say to drain the oil out right after break-in. Thoughts?
I've only run 2 aftermarket camshafts, both of them gave me wear problems with the gear drive that drove the distributer on a ford 302, and on a ford 250 six. One was from crow cams, which used to be a popular well known company here is Australia, the other was branded as a "heatseeker" and sold in speed shops. Now I won't run aftermarket cams because of the short gear life, they are cutting their own throats by offering these dodgy camshafts, I for one won't be buying anymore of their crap product, how many other people have had the same experience? David Vizard suggests that we should be getting the optional hard coating applied to cams when we order them, I think that it's hard anodizing, but I haven't seen it offered here in aus. Edit, An Australian oil/additive company has a 20/50 oil with plenty of zinc in it, and the blurb on the bottle says that it's for older engines that run flat tappet cams, it's cheap too, around $50. (Aus) for 5 litres, the brand is Nulon for those interested.
Cool info!!
Good visuals of the result!
What year d8d th8s start?
Great video, I'll be curious to see what brand of camshaft you'll use in the GMC engine rebuild,or does CZcams rules say that's not allowed?
It’s already in the engine and in the truck! Had a few hours today to work on it. Gotta get it running in the next 30 days to try and make an event! It’s a comp hydraulic roller with their new evolution lifters. I bought it so no rules to break!
Been stockin up on parts to rebuild my 350 and got a new summit 1785 cam and new lifters sitting on the shelf, after seeing all kinds of videos about flat tappet failures i'm paranoid about a cam failure 🤞😂
I’d be more paranoid about using white box, knock off house brand crap. Go with quality parts.
What's your take on reground roller cams? from companies like Delta Cams... Great info had to sub to get all the updates
Nothing wrong with a reground cam. Those companies that offer that service generally know the limits on each material. The only issue is you’re not going to make drastic changes to something. It’s a nice way to save a little money but it’s something I wouldn’t use. A new cam isn’t really that much money.
thank you for your input @@MuscleCarSolutions
I'd like to know:
1) what are the benefits of re-grinding an OEM shaft and is it cost effective compared to a new cast cam?
2) What are your thoughts on cryogenically treating a new cast cam?
Regrinds are tricky. They’ll test for hardness once they get it but you’re very very limited on what it can be ground to. The cryo treatment in cams hasn’t really taken off. Not sure what that is. Or there is little actual benefit. If there were, you’d be hearing about it from the big name engine builders and cam manufacturers. Maybe it will evolve into something down the road.
@@MuscleCarSolutions cryo took a while for it to be accepted in the aftermarket even though it's proven in other fields. it's not uncommon to now get brake rotors so treated but it's been in the firearm and edged weapon field as well as others for decades.
regrinds seem to be a thing but i'm not sold yet.
Ps. I ran a 1964 1/2 289 ford engine that I rebuilt using flat tappet cam + tappet s for 10 years without failures. Just another old reference for the road. Chet
You can heat treatment or nitride a camshaft after you grind it if you know how to do it..Only a dummy would rely on the factory heat treatment. But usually it is the lifters that eats the camshaft. And if that happens it's because you have a lubrication issue not a heat treatment issue.
Awsome, Can you pls ask billy to discribe lobe centrelines as in lobe timeing not overlap . Mike
That information is likely in his new book.
Back in the 80's we built so many engines no trouble. No flat tappet cam issues. Guess it's more oil, and lifter issues.
I worked for a engine remanufacturer when I was a kid. The company sold hundreds of mostly small block and big block Chevys that were basically stock rebuilds. Every month we’d get a couple back that had destroyed themselves. It was always blamed on the cam and lifter quality if that’s what let go. Today, there have been more investigative looks at why. We’re going to cover a big one that no one has really gone in depth on when we do the final video in this series on lifters.
We heated our Rods at 1800 for 2 hours on a conveyor. a few things only were induction HT.
I like your video. Maybe you should help me out what type of cam's would you recommend for a 5.3 lm7 Chevy avalanche everyday driving though about 195 /192 /482/487/ 116 dg lobe i want go a step higher than this one . I am a old school I have not rebuild a motor since 1984 help me out with some tips thank you very much 👍👍
Would need quite a bit more info if you’re. Looking for a cam recommendation. There’s lots to consider to find the right profile but there are some really good options available if you want some more mid range torque, low end torque.
@@MuscleCarSolutions stock heads stock crankshaft. Motor bore 20 over flat top Pistons I do not want a big thumper and a good price range camshaft
My builder said the melling stuff is all he trusts atm. That and using a damn good break in oil and a top notch zinc oil forever after .
Thermal cycling before heat treat would help those cast cores greatly. That grain structure is huge..
Yes, you are correct, Submerge, the part in 50 % water and 50 % Hydrocoric acid, Rinse with cold water, then blow off the part with compressed air. This will let you see the grain structure on how it was rolled, made, or cast. Used W D 40 to bring out grain structure.
Dude! You need to get this info to those core manufacturers and tell them they’ve been doing to wrong for 50 years!
@@MuscleCarSolutions I've talked to a friend of mine who works for comp cams. They are unwilling to incur the costs of the procedure. Not sure why you're being sarcastic with subs. Definitely not a way to keep people around...
Comp doesn’t make the cores. They are bought from the same place all the others buy from. They are the ones who dictate the process. The only thing they will adjust is the range the cam can be ground on. Casting, journal finishing, hardening are all decided upon by those suppliers. The heat treating is done by the core supplier, not by the manufacturer that puts their final grind on the cam.
Normally, the customer buys only 1 camshaft & the presented RW test is highly Destructive
You have any experience with getting cam/lifters pre broken in? Think it’s a viable option ? ..I read places like cam research Corp can do it .
There’s on gigantic factor in that. Unless you’re sending them your block, it ignores the most neglected part of an engine rebuild. The condition of the lifter bores.
There a something I saw on the cross- sectioned cam. If you look at the lobes right next to the journal, the amount of gray fades away and tapers away from the journal. That tells me that the heat treating is being causing the heat is being. bled away from the journals. More time needs to be added to the heat treating to keep this incomplete full heat treating
I’m considering asking Billy Godbold for a follow up interview on some examples of this, but as it was explained to me, these were perfectly within spec. But it costs a decent amount of money to cut these up and it’s just not in the budget right now. Maybe next year.
I have now watched about a dozen trades persons work through the possibilities of cam/tappet failure modes. The problem exists in the metallurgy of each of the individual components. So what makes up the metals used to make either of these two components? Also, which process that is used, such as cast iron or billet steels. There can be many alloy that can be used in the final product. Some alloys are cheap, like cast iron, and have certain properties. Then there is the more exotic alloys that get used in bitter stock for cams and lifters. I’m not going to pick an alloy, that’s the manufacturers job. Most companies heat treat before grinding, then just ship parts from there and take their lumps from there on. But, what if you do you hardness testing and find numbers too low to suit the required hardness or are just marginal at best. It appears to me that heat treating before grinding is not a bad thing, because the grinding is more predictable. But what about heat treating after grinding. I believe hardness will be much more predictable and have numbers that will meet the wear factors under load. Same process for lifters.
God help the supplier who buys a cheap alloy recipe, that fails, when just a little more chrome or other more predictable
hardness features, and gets far better wear factors. Or are we trying to copy what the Chinese are using?
Try finding on CZcams the “FRAME “ series that show the Porsche displays on their cam lobes that can be seen on their videos. Do you think Porsche uses cheap alloys?
It’s ALL in the metallurgy guys. Cheap alloy equals inferior products. Try to find what Mopar had to do when they had failure after failure on their lifters etc.
Chet
Id like to share an unpopular opinion not many folks mention. Im still wondering where the manufacturers got the idea to run in a cam at above 2k rpm for break in. Friction and speed is far lower at idle speed. Oil still comes around the lifter and drips down on the cam lobe as ive seen in an engineering video with a camera looking at a lifter during idle operation. 800rpm idle with good correct spring pressure and quality oil should slow buff the parts? Oil sling cant possibly be accurate off the rods at cold start which most break ins are run at. I have personally never ran a (break-in) at any engine speed above 1500 during the comp lifter failures never had an issue. Id like to hear some professional opinions as well!
Harden too deep, and it does become more brittle. But cast iron pretty much arrives brittle to begin with.
I had one snap in a gen5 454 when it tossed a rod and broke a piston.
Checkin in
Cheers!
I wish some Similar Hardness tests of Flat Tappets would also be performed.....Since 1993, when frequent Flat Tappet camshaft Break-in Failures were being Noticed, No one has Yet Confirmed that a Soft, out of Hardness specs Camshaft was Involved...It's Very Interestingthat that most people Daily driving Older, High Milage Cars & Trucks with factory Original FT cams & Lifters & had No camshaft or Lifter problems.....Numerous FT Rockwell Hardness Testing Still hasn't found No Soft heat treatment New Camshaft core issues....Inadequate or total Lack of camshaft Lobe Taper (1.5° -- 3.0°) Has been Observed with Failed & New recently ground Camshafts.....Incorrectly Ground FT Lifter Face Radius issues Are being Reported......
You can snap a small block Chevrolet camshaft by making it off the work bench but you won't do it with a 351 Windsor or Modified Ford camshaft.
If it’s a cast cam core it will snap with ease if dropped. Doesn’t matter what it fits.
How Close was I to Imminent flat Tappet camshaft Disaster ?? .....Just got around to Inspecting my 1970 Hydraulic flat tappet Lifters that were removed in 1972 from a factory Original 1970 426 hemi engine with Only 10,500 miles.....One Lifter Face has a perfectly Centered, smooth, 0.660" wide, 0.003" deep, flat Depression.....Assuming that Lifter Face originally had the Standard 0.002--0.003 tall Face Dome, That's 0.006" lifter Face Wear in Only 10,000 miles !! ..... Is This a 1970--1972 time frame Example of Early Accelerated Factory Original flat Tappet lifter wear & Imminent engine Killing Failure ?? .....Apparently, the lifter Was Rotating normally until Removed in 1972 for Solid Lifter upgrade. .....Only good 10W30 --- 20W50 Pennzoil was used with Very frequent Oil & Filter changes.... The 1970 hemi engine used Hydraulic Lifters with 320# Open single Springs with Damper....Haven't had a chance to Inspect the other 15 Lifters.....
Improper break in is usually the culprit.
I was wrong . Thank`s for letting me know .
From my research they all come from 2 companies. Engine power components, and camshaft machine Corp. both In Michigan.
The grain stricture between cast steel and tool steel is also completely different.
Stricture? Is that the Gospel of Tubelcain?
Great video, and please don't push any more cam shafts off the table lol 🤣. Take Care
It hurt my feelings to do it. 😂
I usually blame the oil and start there.
Do not be fooled into just trying to scratch the surface. The real heat treating has to go deeper than skin deep.
It's usually the builders fault
Bloodviking
I agree about 90% im also starting to question the engineers.....yes or maybe the bookies at the cam manufacturers. Where did the break in procedure come from? 2krpm for 30 minutes makes no sense when idle speed produces good oil flow and pressure and at 800rpm the cam is only spinning at 400rpm that shouldnt build anywhere near the heat that is at cam speeds of 1k up for (break-in) the whole rod oil sling theory is not false but is not fully true. Until oil is hot it isnt being slung out as fast or in a fog or mist yet. The oil does come around the lifter bore and lube the cam at idle. If id didnt all the taxi cabs and cop cars since the 50s wouldve all disintegrated at idles set to 500-800 rpm. I do not run the 2500 rpm break in and have had no failures even with cheap chinese lifters.
Ford guy , Cam Research has Cam King video. Break in service for Ford cams. Run stocker type springs? Waiting for Billy Cam Godbold to offer up nitrided lifters or Cam advice , part 3. Sadly this is geek stuff for the few.
They won’t do a nitrited lifter. They already have the solution with their new flat tappet lifter.
The DLC lifter ? Seen it mentioned for Chevys. Eyes be looking .
I knew you could do it
😆 it was a long night but here it is!
@@MuscleCarSolutions
Well thank you for the extra effort
I now know a little bit more about cam shafts.
Not sure how I’m going to apply that knowledge yet but I’m sure it will come in handy.
@@tommytron2000 it was a topic that needed to be covered in the series, plus every other video I get tagged in just talks about theory. I wanted to SHOW it so folks would know what it actually looks like. Thanks! I just subscribed to your channel.
@@MuscleCarSolutions
Thank you for the sub!!
We got a few videos of us fumbling with our machines you might get a few laughs out of.
I’m gonna sit down after dinner and watch a few!
Wow didn't know they were so brittle.
Extremely!
Caused by not thermal cycling after it leaves the casting process.
I think all cast iron is brittle. The obvious exception might be ductile iron.
Eastwood couldn't pay me enough money to place one of their decals on anything I own. Eastwood is just another Harbor Freight with blue paint. I got stuck with one of their MIG welders and they would not stand behind it or their word. Eastwood is garbage.
Maybe they just don’t like you? They’ve treated me extremely well and even took care of a defective tool and one that I broke that was my fault.
Top notch knowledge 👌
Roller cams are less likely to fail vs flat tappet cams
Tell that to Chrysler. Hemi roller lifter failures everywhere.
12:43 Always lick the chicken grease off your fingers before handling a camshaft. 😁
It was delicious.
The cast cores can't stand shock
Reasons why cams fail.
Improper break in procedure
Cheap Chinese lifters and parts
Cam not in proper position
Cheap break in oil
Too much spring pressure for break in
Cam not broke in long enough
Bad core possible
Used lifters with new Cam
New lifters used Cam, best to have both new
Other valve components junk or not in alignment
Mismatched components
Lifter bores not straight
Improper clearences
Used Cam bearings
Cam bearing oil holes misaligned
Cam gears misaligned
Bloodviking
I've been told that the problem of cam failures is there are no new hydraulic flat tappet lifters being manufactured, and that what's being sold are remanufactured lifters that have had the plunger removed, the bore honed, and the heal ground .005-.035, with some having the bores honed too large, too much removed from the heal, not allowing the oil holes to line up in the lifter bore, or the crown on the heal being incorrectly ground.
That would be the most illogical assumption ever. The lifter manufacturers have made it pretty clear their primary support is for the OE demand of roller lifters and cam cores. Those assemblies have a much higher cost and for sure when you compare dollar for dollar, the roller products bring in the bigger cash flow. Why would they attempt to remanufacture a wearable part? There is an overall height to any lifter. If the cam grinder were to take these in with a much shorter height (and one that would also affect the seat height of the plunger) then everything would have to change. There would be no factory pushrod lengths used as they would all need to be longer to take up that shortage on the lifter side. No machinist would stand for that. No, flat taper lifters are rebuilt. Not on this day and age. It doesn’t make financial sense or everything it would affect down the supply chain.
There's a CZcams video by a guy who sourced his parts from Summitt, and the Summitt tech told him what I posted.
Daniel Powell of Powell machine has a you tube channel and has a very good video on this subject. Powell has the equipment to test Rockwell hardness, to regrind cams, new cam cores, and to measure the crown on the lifter heal and to regain them as well, and he tests several manufacturers lifters and finds they are all being incorrectly ground and refuses to use customer supplied lifters without regrinding them.
From what I can tell, all of the cam manufacturers are buying and packaging remanufactured flat tappet hydraulic lifters and not doing the work themselves. While I don't doubt there are some cam manufacturers making new roller hydraulic lifters, it doesn't appear that any of them are making new flat tappet hydraulic lifters.
@@billpinkston1464 that’s some interesting opinions, but there’s still no chance that a company would further complicate a process that they have no desire to be in the first place. And even if there was a financial benefit to them to regrind a lifter, it’s minimal. The math doesn’t add up. I know who the two US manufacturers are that are the primary sources of flat tappet lifters and neither and remanufacturing lifters. When it comes to crown and taper. Those are factors that are dependent on each other. To make a blanket statement that all lifters have incorrect crown, doesn’t take into account the other half of the equation, which is the cam. The two work together. So while I know of one retailer who wants his cams ground with a ridiculous taper, it’s because they use an off shore lifter that has an equally ridiculous crown. Of the big name cam manufacturers in the market that sell flat tappet cams and lifters, none make them in their own facility. They all buy them from the two companies in the US that still make them. The rest come from off shore.
Most cam failures are not from cam hardness failure.